J. Nat. Prod. 2006, 69, 1237-1240
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Phenolic Constituents of the Roots of Sophora flaWescens Chien-Chang Shen,† Ting-Wei Lin,‡ Yu-Ling Huang,† Shr-Ting Wan,† Bor-Jinn Shien,‡ and Chien-Chih Chen*,†,§ National Research Institute of Chinese Medicine, No. 155-1, Sec. 2, Li Nung Street, Peitou, Taipei, Taiwan, Republic of China, Institute of Chemistry, Chung Yuan Christian UniVersity, Chung-Li, Tao-Yuan Hsien, Taiwan, Republic of China, and Institute of Life Science, National Taitung UniVersity, Taitung, Taiwan, Republic of China ReceiVed April 28, 2006
From the roots of Sophora flaVescens collected in Taiwan, four new prenylflavonoids, sophoraflavanone K (1), sophoraflavanone L (2), 8-lavandulylkaempferol (3), and cyclokuraridin (4), a new arylbenzofuran, 2-(2,4-dihydroxy5-prenylphenyl)-5,6-methylenedioxybenzofuran (5), and a new prenyldibenzoyl derivative, sophoradione (6), were isolated. The structures of 1-6 were determined by spectroscopic data analysis. Compounds 2-6 were evaluated for cytotoxic activity against the KB epidermoid carcinoma cell line. The root of Sophora flaVescens Ait. (Leguminosae) is a Chinese herb found to exhibit antibacterial, anti-inflammatory, antipyretic, antiarrhythmic, antiasthmatic, antiulcerative, and antineoplastic effects and is used to treat jaundice, leukorrhea, carbuncles, pyogenic infections of the skin, scabies, enteritis, and dysentery.1 In previous studies, quinolizidine alkaloids, flavonoids, benzofuran, and triterpenoids have been isolated from the roots of S. flaVescens.2-16 In the course of screening for cytotoxic constituents from herbs growing in Taiwan, we found that a crude extract of the roots of S. flaVescens exhibited cytotoxic activity against KB tumor cells. In this paper, we report the isolation and structure elucidation of six new compounds (1-6) and their cytotoxic activities against a KB tumor cell line. The dried, chipped roots of S. flaVescens were extracted with MeOH. The MeOH extract was suspended in water to give watersoluble and water-insoluble portions. The water-insoluble portion was chromatographed repeatedly using Sephadex LH-20, silica gel, preparative TLC, and HPLC to afford six new compounds, sophoraflavanone K (1), sophoraflavanone L (2), 8-lavandulylkaempferol (3), cyclokuraridin (4), 2-(2,4-dihydroxy-5-prenylphenyl)-5,6-methylenedioxybenzofuran (5), and sophoradione (6). The HREIMS of compound 1 indicated a molecular ion peak at m/z 454.1991, which corresponded to the molecular formula C26H30O7. Hydroxyl (3395 cm-1) and carbonyl (1635 cm-1) absorptions were observed in the IR spectrum. The 1H NMR spectrum of 1 showed resonances for a methoxy group at δH 3.67 and a chelated hydroxyl group at δH 12.40 and typical flavanone17 signals at δH 2.55 (1H, dd, J ) 2.5, 17.0 Hz, H-3R), 3.08 (1H, dd, J ) 13.0, 17.0 Hz, H-3β), and 5.57 (1H, dd, J ) 2.5, 13.0 Hz, H-2). It also exhibited signals for a lavandulyl group4,17 at δ 1.44 (3H, s, H3-6′′), 1.50 (3H, s, H3-7′′), 1.58 (3H, d, J ) 1.0 Hz, H310′′), 2.01 (2H, m, H2-3′′), 2.49 (1H, m, H-2′′), 2.53 (2H, m, H21′′), 4.43 (1H, br s, H-9′′b), 4.47 (1H, d, J ) 1.0 Hz, H-9′′a), and 4.93 (1H, t, J ) 2.5 Hz, H-4′′). Like other lavandulyl flavonoids isolated from S. flaVescens, the absolute configuration at C-2′′ of the lavandulyl group in compound 1 has not been determined.18 The HMBC correlations of OH-5 (δH 12.40)/C-6, C-10 and H-1′′/ C-7, C-9 clearly revealed that the lavandulyl group is linked to C-8. Furthermore, two singlet signals at δH 6.35 (1H) and 6.98 (1H) suggested that the B-ring of 1 is 1,2,4,5-tetrasubstituted. In the NOE experiment, irradiation of the methoxy group at δH 3.67 caused enhancement of H-6′ (δH 6.98), correlating with C-2 in the HMBC spectrum. Thus, the linkage of the methoxy group to C-5′ * To whom correspondence should be addressed. Tel: +886-2-28201999, ext. 6701. Fax: +886-2-28264276. E-mail:
[email protected]. † National Research Institute of Chinese Medicine. ‡ Chung Yuan Christian University. § National Taitung University. 10.1021/np060189d CCC: $33.50
was confirmed. On the basis of the above evidence, the new compound sophoraflavanone K (1) was determined to be 5,7,2′,4′tetrahydroxy-8-lavandulyl-5′-methoxyflavanone. The EIMS of 2 showed a molecular ion at m/z 424, corresponding to a molecular formula of C25H28O6. The IR spectrum exhibited hydroxyl (3432 cm-1) and carbonyl (1629 cm-1) absorptions. The NMR signals at δH 2.77 (1H, dd, J ) 2.8, 17.2 Hz), 3.11 (1H, dd, J ) 12.8, 17.2 Hz), and 5.67 (1H, dd, J ) 2.8, 12.8 Hz) indicated that 2 is also a flavanone. In the 1H NMR spectrum of 2, an aromatic proton at δH 6.13 (s), an ABX system of aromatic protons at δH 6.47 (1H, d, J ) 2.4 Hz), 6.43 (1H, dd, J ) 2.4, 8.4 Hz), and 7.33 (1H, d, J ) 8.4 Hz), and a chelated hydroxyl group at δH 12.26 were apparent. Also revealed were a 3,3-dimethylallyl group at δH 1.58 (3H, s, H3-4′′), 1.61 (3H, s, H3-5′′), 3.22 (2H, d, J ) 7.2 Hz, H-1′′′′), and 5.15 (1H, t, J ) 7.2 Hz, H-2′′) and a 3,3-dimethylallyloxy moiety at δH 1.76 (3H, s, H-4′′′), 1.78 (3H, s, H-5′′′), 4.63 (2H, d, J ) 6.8 Hz, H-1′′′), and 5.49 (1H, t, J ) 6.8 Hz, H-2′′′). The 3,3-dimethylallyl group was assigned to C-8, which was supported by HMBC cross-peaks: OH-5/C-5, C-6, and C-10 and H-1′′/C-3′′, C-7, C-8, and C-9. HMBC connectivities from H-1′′′ to C-3′′′ and C-7 indicated that the 3,3-dimethylallyloxy moiety was attached to C-7. Thus, compound 2 was characterized as 5,2′,4′trihydroxy-7-(γ,γ-dimethylallyloxy)-8-(γ,γ-dimethylallyl)flavanone and has been named sophoraflavanone L. The molecular formula of 3 was shown to be C25H26O6 by HREIMS analysis. The IR spectrum exhibited the presence of hydroxyl (3316 cm-1) and carbonyl (1629 cm-1) groups. UV absorptions at λmax 373, 307, and 272 nm indicated its flavonol character. The 1H NMR spectrum of 3 showed an aromatic proton singlet at δH 6.20 (H-6) and a typical A2B2 system at δH 6.90 (2H, d, J ) 9.0 Hz, H-3′,5′) and 8.08 (2H, d, J ) 9.0 Hz, H-2′,6′). Like compound 1, compound 3 also displayed the signals of a lavandulyl group at δH 1.38 (3H, s), 1.46 (3H, s), 1.59 (3H, s), 2.05 (2H, m), 2.52 (1H, m), 2.84 (2H, m), 4.44 (1H, br s), 4.50 (1H, br s), and 4.91 (1H, m). From the HMBC spectrum, correlations between OH-5 (δH 11.98) and C-5, C-6, and C-10 as well as between H21′′ (δH 2.84) and C-7, C-8, and C-9 were evident, which was used to assign the linkage of the lavandulyl group to C-8. Therefore, compound 3 was identified as 8-lavandulylkaempferol. The molecular formula of 4 was shown to be C26H30O6 on the basis of ESIMS and from the 1H and 13C NMR spectra. Comparison of its 1H and 13C NMR data (δH 8.02 and 8.15; δC 193.7) with kuraridin10 and other chalcones indicated that 4 is a chalcone. The 1H NMR spectrum of 4 showed a methoxy group (δ 3.91), an H ABX system of aromatic protons [δH 6.44 (dd, J ) 2, 8.8 Hz), 6.49 (d, J ) 2.0 Hz), and 7.52 (d, J ) 8.8 Hz)], an aromatic proton [δH 5.91 (s)], and a chelating hydroxyl group (δH 15.08). It also revealed a 2,2-dimethyldihydropyran moiety [δH 1.23 (3H, s), 1.42
© 2006 American Chemical Society and American Society of Pharmacognosy Published on Web 08/04/2006
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Journal of Natural Products, 2006, Vol. 69, No. 8
Notes
Chart 1
(3H, s), 1.73 (1H, m), 2.14 (1H, dd, J ) 10.0, 16.8 Hz), and 2.72 (1H, dd, J ) 5.2, 16.8 Hz)] and a 3,3-dimethylallyl group [δH 1.53 (3H, s), 1.66 (3H, s), 1.87 (1H, m), 2.27 (1H, m), and 5.20 (1H, t, J ) 6.8 Hz)]. The locations of the pyran ring and 3,3-dimethylallyl group in 4 were established by HMBC analysis, in which crosspeaks were observed between OH-5 (δH 15.08) and C-1 and C-3, between H-1′′ (δH 2.14 and 2.72) and C-2, C-4, C-3′′, and C-8′′, and between H-2′′ (δH 1.73) and C-3 and C-4′′. Thus, the pyran ring was determined to be fused to C-3 and C-4 of the benzene ring and the 3,3-dimethylallyl moiety was attached to C-2′′. The position of the methoxy group was assigned at C-6 by a NOE measurement, in which irradiation of methoxy protons at δH 3.91 caused the enhancement of H-5 (δH 5.91). Accordingly, the structure of cyclokuraridin (4) was determined as 2,2′,4′-trihydroxy-6methoxy-6′′,6′′-dimethyl-5′′-prenyldihydropyrano[2′′,3′′:4,3]chalcone. Compound 5 was obtained as a brown solid, and its molecular formula was established as C20H18O5 by HREIMS. The IR spectrum of 5 showed the presence of hydroxyl (3353 cm-1), aromatic ring (1619, 1608, 1498 cm-1), and methylenedioxy (1035, 936 cm-1) groups, and the UV spectrum with absorption maxima at λmax 322 and 347 nm was consistent with a 2-phenylbenzofuran skeleton.19 The 1H NMR spectrum of 5 showed four aromatic singlet signals at δH 7.00, 7.09, 7.14, and 7.60, an olefinic proton at δH 6.60, one methylenedioxy group at δH 6.01, and a 3,3-dimethylallyl group at δH 1.75 (3H, s), 1.77 (3H, s), 3.34 (2H, d, J ) 7.5 Hz), and 5.38 (1H, m). In the HMBC spectrum, cross-peaks between H-3 and C-1′, C-4, and C-8, between H-6′ and C-2, C-2′, C-4′, and C-1′′, and between H-1′′ and C-4′, C-6′, and C-3′′ indicated the linkage of the 3,3-dimethylallyl group to C-5′. From the above results, compound 5 was determined as 2-(2,4-dihydroxy-5-prenylphenyl)5,6-methylenedioxybenzofuran. Compound 6 was obtained as a yellow-green oil, and its molecular formula was established as C25H28O7 by HREIMS. The
IR spectrum of 6 revealed the presence of hydroxyl (3322 cm-1) and carbonyl (1619 cm-1) groups. The 13C NMR and DEPT spectra showed that there were three methyls, three methylenes, one methoxy, six methines, 10 quaternary carbons, and two carbonyl carbons present in the molecule. In the 1H NMR spectrum, signals for a methoxy group at δH 3.51 (3H, s), a lavandulyl group at δH 1.56 (3H, s), 1.63 (3H, d, J ) 1.2 Hz), 1.72 (3H, s), 2.14 (2H, m), 2.60 (1H, m), 2.70 (2H, m), 4.58 (1H, br s), 4.62 (1H, br s), and 5.07 (1H, m), and a chelated hydroxyl group at δH 12.82 (1H, s) were observed. Also revealed was an ABX system of protons at δH 6.42 (1H, d, J ) 1.6 Hz), 6.43 (1H, dd, J ) 1.6, 7.2 Hz), and 7.28 (1H, d, J ) 7.2 Hz). The HMBC spectrum further showed the correlations of OH-2/C-1 and C-3, H-6′ (δH 7.28)/C-R (δC 195.4), C-2′, and C-4′, and H-1′′ (δH 2.70)/C-2, C-3, and C-4, which suggested the linkage of the lavandulyl group at C-3. The position of the methoxy group was assigned at C-6 by the NOE measurement, in which enhancement was observed for H-5 (δH 6.06) after irradiation of methoxy protons at δH 3.51. Thus, the new compound sophoradione (6) was assigned as 2,4,2′,4′-tetrahydroxy-3-lavandulyl-6-methoxybenzil. Isolates 2-6 were tested for cytotoxic activity against the KB tumor cell line. It was found that compounds 2-6 showed IC50 values of 7.1, 24.3, 15.1, 8.0, and 29.4 µg/mL, respectively. Experimental Section General Experimental Procedures. Melting points were determined on a Yanaco MP-I3 micro-melting point apparatus without correction. Optical rotations were taken with a JASCO DIP-370 digital polarimeter. IR spectra were recorded on a Nicolet Avatar 320 FT-IR spectrometer. UV spectra were measured on a Hitachi U-3200 spectrophotometer. NMR spectra were recorded at 500 MHz for 1H and 125 MHz for 13C on a Varian Unity INOVA-500 spectrometer or at 400 MHz for 1H and 100 MHz for 13C on a Bruker AVANCE-400 spectrometer. EIMS and HREIMS were obtained using Finnigan MAT GCQ and JEOL
Notes
JMS-700 spectrometers, respectively. LCMS spectra were taken on a Finnigan LCQ. HPLC was performed on a Hewlett-Packard series 1100 pump system equipped with a Hewlett-Packard UV/vis detector. Plant Material. The roots of Sophora flaVescens were collected in July 2003, from Hualien Hsien, Taiwan, and authenticated by Mr. J. C. Ou, Research Fellow, National Research Institute of Chinese Medicine. The voucher specimen (NRICM-03-011) was deposited at the Herbarium of the National Research Institute of Chinese Medicine, Taipei, Taiwan. Extraction and Isolation. The dried, chipped roots of S. flaVescens (8 kg) were extracted with MeOH (80 L × 3). The combined extracts were evaporated in vacuo to give a black residue, which was suspended in water (10 L) and centrifuged (9000 rpm, 30 min) to give watersoluble and water-insoluble portions. The water-insoluble portion was chromatographed on a silica gel (70-230 mesh) column eluted with gradient solvent systems of n-hexane-EtOAc (10:1 f 1:5), EtOAc, and EtOAc-MeOH (10:1 f 1:5) to yield 10 fractions. Fraction 4 (nhexane-EtOAc ) 2:1 eluate) was further chromatographed on Sephadex LH-20 (MeOH) and silica gel (70-230 mesh, CHCl3-MeOH ) 1:0, 25:1, 20:1, 10:1) columns to yield four fractions, 4-1-4-4. Fraction 4-3 was purified with a Sephadex LH-20 (MeOH) column to afford 3 (114 mg). Fraction 5 (n-hexane-EtOAc ) 1:1 eluate) was chromatographed on Sephadex LH-20 (MeOH) to yield six fractions, 5-1-5-6. Fraction 5-2 was further separated with silica gel (230-400 mesh, CH2Cl2-acetone ) 20:1) and Sephadex LH-20 (MeOH) columns and then with preparative TLC (CH2Cl2-acetone ) 10:1) to give 1 (5.5 mg) and 6 (17.5 mg). Fraction 5-5 was further purified with silica gel (230400 mesh, n-hexane-acetone ) 3:1) and preparative TLC (CH2Cl2acetone ) 10:1) to afford 5 (7.5 mg). Fraction 7 (EtOAc eluate) was subjected to Sephadex LH-20 (MeOH) and silica gel (230-400 mesh, CHCl3-MeOH ) 20:1 f 10:1) columns to give 2 (21 mg) and 4 (8 mg). Sophoraflavanone K (1): brown solid; [R]25D +50 (c 0.1, MeOH); UV (MeOH) λmax (log ) 294 (4.42), 231 (sh), 203 (4.85) nm; IR (KBr) νmax 3395, 1635, 1519, 1451, 1377, 1345, 1309, 1198, 1156, 1107 cm-1; 1 H NMR (Me2CO-d6, 500 MHz) δ 12.40 (1H, s, OH-5), 6.98 (1H, s, H-6′), 6.35 (1H, s, H-3′), 5.89 (1H, s, H-6), 5.57 (1H, dd, J ) 2.5, 13.0 Hz, H-2), 4.93 (1H, t, J ) 2.5 Hz, H-4′′), 4.47 (1H, d, J ) 1.0 Hz, H-9′′a), 4.43 (1H, br s, H-9′′b), 3.67 (3H, s, OCH3-5′), 3.08 (1H, dd, J ) 13.0, 17.0 Hz, H-3β), 2.55 (1H, dd, J ) 2.5, 17.0 Hz, H-3R), 2.53 (2H, m, H2-1′′), 2.49 (1H, m, H-2′′), 2.01 (2H, m, H2-3′′), 1.58 (3H, d, J ) 1.0 Hz, H3-10′′), 1.50 (3H, s, H3-7′′), 1.44 (3H, s, H3-6′′); 13 C NMR (Me2CO-d6, 125 MHz) δ 197.2 (C, C-4), 166.5 (C, C-7), 162.3 (C, C-9), 161.8 (C, C-5), 148.4 (C, C-4′, C-8′′), 148.0 (C, C-2′), 141.4 (C, C-5′), 130.9 (C, C-5′′), 123.8 (CH, C-4′′), 115.7 (C, C-1′), 111.6 (CH, C-6′), 110.7 (CH2, C-9′′), 107.8 (C, C-10), 103.6 (CH, C-3′), 102.2 (C, C-8), 94.6 (CH, C-6), 74.5 (CH, C-2), 56.6 (CH3, OCH3-5′), 46.9 (CH, C-2′′), 42.2 (CH2, C-3), 31.5 (CH2, C-3′′), 26.7 (CH2, C-1′′), 25.2 (CH3, C-7′′), 18.2 (CH3, C-10′′), 17.3 (CH3, C-6′′); EIMS m/z 454 [M]+ (7), 436 (20), 331 (14), 313 (100), 272 (11), 165 (9); HREIMS m/z 454.1991 (calcd 454.1992 for C26H30O7). Sophoraflavanone L (2): colorless prisms; mp 125-127 °C (MeOH); [R]25D (0 (c 0.5, MeOH); UV (MeOH) λmax (log ) 341 (3.80), 292 (4.53), 220 (sh) nm; IR (KBr) νmax 3432, 1629, 1598, 1461, 1361, 1303, 1230, 1177, 1088 cm-1; 1H NMR (Me2CO-d6, 400 MHz) δ 12.26 (1H, s, OH-5), 7.33 (1H, d, J ) 8.4 Hz, H-6′), 6.47 (1H, d, J ) 2.4 Hz, H-3′), 6.43 (1H, dd, J ) 2.4, 8.4 Hz, H-5′), 6.13 (1H, s, H-6), 5.67 (1H, dd, J ) 2.8, 12.8 Hz, H-2), 5.49 (1H, t, J ) 6.8 Hz, H-2′′′), 5.15 (1H, t, J ) 7.2 Hz, H-2′′), 4.63 (2H, d, J ) 6.8 Hz, H-1′′′), 3.20 (2H, d, J ) 7.2 Hz, H-1′′), 3.11 (1H, dd, J ) 12.8, 17.2 Hz, H-3β), 2.77 (1H, dd, J ) 2.8, 17.2 Hz, H-3R), 1.78 (3H, s, H-5′′′), 1.76 (3H, s, H-4′′′), 1.61 (3H, s, H-5′′), 1.58 (3H, s, H-4′′); 13C NMR (Me2CO-d6, 100 MHz) δ 198.4 (C, C-4), 165.6 (C, C-7), 163.5 (C, C-5), 160.4 (C, C-9), 159.4 (C, C-4′), 156.2 (C, C-2′), 138.9 (C, C-3′′′), 131.1 (C, C-3′′), 128.7 (CH, C-6′), 123.6 (CH, C-2′′), 120.2 (CH, C-2′′′), 117.7 (C, C-1′), 109.3 (C, C-8), 107.8 (CH, C-3′), 103.4 (CH, C-5′), 103.4 (C, C-10), 93.8 (CH,C-6), 75.2 (CH, C-2), 66.2 (CH2, C-1′′′), 42.7 (CH2, C-3), 25.9 (CH3, C-5′′), 25.8 (CH3, C-4′′′), 22.3 (CH2, C-1′′), 18.2 (CH3, C-5′′′), 17.8 (CH3, C-4′′); EIMS (30 eV) m/z 424 [M]+ (42), 338 (100), 295 (91), 283 (81), 219 (99), 177 (50), 165 (46); HREIMS m/z 424.1884 (calcd 424.1886 for C25H28O6). 8-Lavandulylkaempferol (3): yellow prisms; mp 175-177 °C; [R]25D +38 (c 0.5, MeOH); UV (MeOH) λmax (log ) 373 (4.22), 307 (4.14), 272 (4.35) nm; IR (KBr) νmax 3316, 1629, 1592, 1529, 1372,
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1309, 1272, 1141 cm-1; 1H NMR (Me2CO-d6, 500 MHz) δ 11.98 (1H, s, OH-5), 8.08 (2H, d, J ) 9.0 Hz, H-2′, 6′), 6.90 (2H, d, J ) 9.0 Hz, H-3′, 5′), 6.20 (1H, s, H-6), 4.91 (1H, m, H-4′′), 4.50 (1H, br s, H-9a′′), 4.44 (1H, br s, H-9b′′), 2.84 (2H, m, H2-1′′), 2.52 (1H, m, H-2′′), 2.05 (2H, m, H2-3′′), 1.59 (3H, s, H3-10′′), 1.46 (3H, s, H3-7′′), 1.38 (3H, s, H3-6′′); 13C NMR (Me2CO-d6, 125 MHz) δ 176.9 (C, C-4), 162.7 (C, C-7), 160.2 (C, C-4′), 160.0 (C, C-5), 155.4 (C, C-9), 148.8 (C, C-8′′), 146.8 (C, C-2), 136.5 (C, C-3), 132.0 (C, C-5′′), 130.4 (CH, C-2′, C-6′), 124.1 (CH, C-4′′), 123.6 (C, C-1′), 116.4 (CH, C-3′, C-5′), 111.7 (CH2, C-9′′), 106.6 (C, C-8), 104.1 (C, C-10), 98.7 (CH, C-6), 48.0 (CH, C-2′′), 32.0 (CH2, C-3′′), 28.0 (CH2, C-1′′), 25.9 (CH3, C-7′′), 19.0 (CH3, C-10′′), 17.9 (CH3, C-6′′); EIMS m/z 422 [M]+ (17), 299 (100); HREIMS m/z 422.1732 (calcd 422.1730 for C25H26O6). Cyclokuraridin (4): red crystals; mp 103-105 °C; [R]25D -170 (c 0.5, MeOH); UV (MeOH) λmax (log ) 390 (4.50), 310 (sh), 254 (3.89) nm; IR (KBr) νmax 3385, 1608, 1456, 1414, 1351, 1309, 1225, 1109 cm-1; 1H NMR (Me2CO-d6, 400 MHz) δ 15.08 (1H, s, OH-2), 8.15 (1H, d, J ) 15.6 Hz, H-β), 8.02 (1H, d, J ) 15.6 Hz, H-R), 7.52 (1H, d, J ) 8.8 Hz, H-6′), 6.49 (1H, d, J ) 2.0 Hz, H-3′), 6.44 (1H, dd, J ) 2.0, 8.8 Hz, H-5′), 5.91 (1H, s, H-5), 5.20 (1H, t, J ) 6.8 Hz, H-4′′), 3.91 (3H, s, OCH3-6), 2.72 (1H, dd, J ) 5.2, 16.8 Hz, H-1′′a), 2.27 (1H, m, H-3′′a), 2.14 (1H, dd, J ) 10.0, 16.8 Hz, H-1′′b), 1.87 (1H, m, H-3′′b), 1.73 (1H, m, H-2′′), 1.66 (3H, s, H-7′′), 1.53 (3H, s, H-6′′), 1.42 (3H, s, H-9′′), 1.23 (3H, s, H-10′′); 13C NMR (Me2CO-d6, 100 MHz) δ 193.7 (C, C-β′), 166.3 (C, C-2), 161.8 (C, C-6, C-4′), 161.0 (C, C-4), 159.6 (C, C-2′), 139.4 (CH, C-β), 133.4 (C, C-5′′), 131.2 (CH, C-6′), 124.7 (CH, C-R), 123.5 (CH, C-4′′), 115.8 (C, C-1′), 109.1 (CH, C-5′), 106.2 (C, C-1), 103.7 (CH, C-3′), 102.8 (C, C-3), 92.3 (CH, C-5), 79.9 (C, C-8′′), 56.1 (CH3, OCH3-6), 41.9 (CH, C-2′′), 30.6 (CH2, C-3′′), 27.8 (CH3, C-9′′), 25.9 (CH3, C-7′′), 22.4 (CH2, C-1′′), 21.3 (CH3, C-10′′), 17.9 (CH3, C-6′′); ESIMS m/z 461 ([M + Na]+). 2-(2,4-Dihydroxy-5-prenylphenyl)-5,6-methylenedioxybenzofuran (5): brown solid; UV (MeOH) λmax (log ) 347 (4.48), 322 (4.46), 281 (4.10) nm; IR (KBr) νmax 3353, 1619, 1608, 1498, 1461, 1372, 1314, 1230, 1172, 1141, 1120, 1035, 936 cm-1; 1H NMR (Me2CO-d6, 500 MHz) δ 7.60 (1H, s, H-6′), 7.14 (1H, s, H-3), 7.09 (1H, s, H-4), 7.00 (1H, s, H-7), 6.60 (1H, s, H-3′), 6.01 (2H, s, OCH2O), 5.38 (1H, m, H-2′′), 3.34 (2H, d, J ) 7.5 Hz, H-1′′), 1.77 (3H, s, H3-4′′), 1.75 (3H, s, H3-5′′); 13C NMR (Me2CO-d6, 125 MHz) δ 156.4 (C, C-4′), 154.2 (C, C-2), 154.1 (C, C-2′), 149.4 (C, C-8), 146.3 (C, C-6), 145.3 (C, C-5), 131.9 (C, C-3′′), 127.7 (CH, C-6′), 124.3 (CH, C-2′′), 124.2 (C, C-9), 120.7 (C, C-5′), 110.6 (C, C-1′), 104.5 (CH, C-3), 103.8 (CH, C-3′), 102.0 (CH2, OCH2O), 99.8 (CH, C-7), 93.7 (CH,C-4), 28.5 (CH2, C-1′′), 25.9 (CH3, C-4′′), 17.8 (CH3, C-5′′); EIMS m/z 338 [M]+ (100), 283 (71), 255 (9), 226 (8); HREIMS m/z 338.1154 (calcd 338.1154 for C20H18O5). Sophoradione (6): yellow-green oil; [R]22D +6 (c 0.5, MeOH); UV (MeOH) λmax (log ) 311 (4.60), 276 (sh), 236 (sh) nm; IR (liquid film) νmax 3322, 1619, 1508, 1445, 1372, 1309, 1240, 1135, 1098 cm-1; 1H NMR (Me2CO-d6, 400 MHz) δ 12.82 (1H, s, OH-2), 7.28 (1H, d, J ) 7.2 Hz, H-6′), 6.43 (1H, dd, J ) 1.6, 7.2 Hz, H-5′), 6.42 (1H, d, J ) 1.6 Hz, H-3′), 6.06 (1H, s, H-6), 5.07 (1H, m, H-4′′), 4.62 (1H, br s, H-9′′a), 4.58 (1H, br s, H-9′′b), 3.51 (3H, s, OCH3-6), 2.70 (2H, m, H2-1′′), 2.60 (1H, m, H-2′′), 2.14 (2H, m, H2-3′′), 1.72 (3H, s, H310′′), 1.63 (3H, d, J ) 1.2 Hz, H3-7′′), 1.56 (3H, s, H3-6′′); 13C NMR (Me2CO-d6, 100 MHz) δ 195.4 (C, C-R), 194.5 (C, C-β), 167.0 (C, C-4), 166.4 (C, C-2), 166.2 (C, C-2′), 166.1 (C, C-4′), 162.1 (C, C-6), 149.0 (C, C-8′′), 134.4 (CH, C-6′), 131.6 (C, C-5′′), 124.4 (CH, C-4′′), 111.4 (CH2, C-9′′), 110.8 (C, C-1′), 109.5 (CH, C-5′), 108.9 (C, C-3), 103.8 (CH, C-3′), 103.2 (C, C-1), 92.0 (CH, C-5), 56.1 (CH3, OCH36), 47.5 (CH, C-2′′), 32.1 (CH2, C-3′′), 27.3 (CH2, C-1′′), 25.9 (CH3, C-7′′), 18.8 (CH3, C-10′′), 17.9 (CH3, C-6′′); EIMS m/z 440 [M]+ (13), 303 (98), 261 (30), 179 (95), 153 (100), 137 (18); HREIMS m/z [M]+ 440.1834 (calcd 440.1835 for C25H28O7). Cytotoxicity Assays. An epidermoid carcinoma cell line (KB; CCRC 60017) was purchased from the Food Industry Research and Development Institute (FIRDI, Taiwan). The cytotoxic activities of the isolated compounds on the KB cell line were examined by a previously described method.20 Camptothecin was employed as the compound for positive control, which exhibited an IC50 value of 2.24 µg/mL under the above conditions. Acknowledgment. This work was supported by the National Science Council, Republic of China, grant NSC94-2323-B-077-001.
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References and Notes (1) Chang, H. M.; But, P. P. H. Pharmacology and Application of Chinese Materia Medica; World Scientific Publishers: Philaldephia, 1986; p 736. (2) Ueno, A.; Morinaga, K.; Okuda, S. Chem. Pharm. Bull. 1978, 26, 1832-1836. (3) Wu, L. J.; Miyase, T.; Ueno, A.; Kuroyanagi, M.; Noro, T.; Fukushima, S. Chem. Pharm. Bull. 1985, 33, 3231-3236. (4) Wu, L. J.; Miyase, T.; Ueno, A.; Kuroyanagi, M.; Noro, T.; Fukushima, S. Yakugaku Zasshi 1985, 105, 736-741. (5) Wu, L. J.; Miyase, T.; Ueno, A.; Kuroyanagi, M.; Noro, T.; Fukushima, S.; Sasaki, S. Yakugaku Zasshi 1985, 105, 1034-1039. (6) Wu, L. J.; Miyase, T.; Ueno, A.; Kuroyanagi, M.; Noro, T.; Fukushima, S.; Sasaki, S. Yakugaku Zasshi 1986, 106, 22-26. (7) Kyogoku, K.; Hatayama, K.; Komatsu, M. Chem. Pharm. Bull. 1973, 21, 2733-2738. (8) Yagi, A.; Fukunaga, M.; Okuzako, N.; Mifuchi, I.; Kawamoto, F. Shoyakugaku Zasshi 1989, 43, 343-347. (9) Yamamoto, H.; Ichimura, M.; Tanaka, T.; Iinuma, M.; Mizuno, M. Phytochemistry 1991, 30, 1732-1733. (10) Yamahara, J.; Mochizuki, M.; Fujimura, T.; Takaishi, Y.; Yoshida, M.; Tomimatsu, T.; Tamai, Y. J. Ethnopharmacol. 1990, 29, 173177.
Notes (11) Ding, Y.; Tian, R. H.; Kinjo, J.; Nohara, T.; Kitagawa, I. Chem. Pharm. Bull. 1992, 40, 2990-2994. (12) Woo, E. R.; Kwak, J. H.; Kim, H. J.; Park, H. J. Nat. Prod. 1998, 61, 1552-1554. (13) Kang, T. H.; Jeong, S. J.; Ko, W. G.; Kim, N. Y.; Lee, B. H.; Inagaki, M.; Miyamoto, T.; Higuchi, R.; Kim, Y. C. J. Nat. Prod. 2000, 63, 680-681. (14) Son, J. K.; Park, J. S.; Kim, J. A.; Kim, Y.; Chung, S. R.; Lee, S. H. Planta Med. 2003, 69, 559-561. (15) Kim, S. J.; Son, K. H.; Chang, H. W.; Kang, S. S.; Kim, H. P. Biol. Pharm. Bull. 2003, 26, 1348-1350. (16) Ding, P.; Chen, D.; Bastow, K. F.; Nyarko, A. K.; Wang, X.; Lee, K. H. HelV. Chim. Acta 2004, 87, 2574-2580. (17) Hatayama, K.; Komatsu, M. Chem. Pharm. Bull. 1971, 19, 21262131. (18) Kuroyanagi, M.; Arakawa, T.; Hirayama, Y.; Hayashi, T. J. Nat. Prod. 1999, 62, 1595-1599. (19) Komatsu, M.; Yokoe, I.; Shirataki, Y.; Chem. Pharm. Bull. 1978, 26, 1274-1278. (20) Shen, C. C.; Ni, C. L.; Huang, Y. L.; Huang, R. L.; Chen, C. C. J. Nat. Prod. 2004, 67, 1947-1949.
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